Variable pitch propeller



April 29, 1941'. R 1 RUTHS yETAL VARIABLE PI'TCH PROPELLER! Filed Jan. 5. 1940 www@ ,Patented Apr.u29, 1941 UNITED STATES "PATENT" 'UFFICE Robert '1. lluthslalfime,

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applieauon'nauaujs, 1940, sum N. 312,224

zown. (c1. 11o-ass) (e1-mud under the t of Maren s, isst, as

amended April a, 192s; 3 1 o. G. '151) very compact and rugged in construction and.

which is very positive and accurate in opera-v tion.

With these and other objects in view, as well as other advantages that may be incident to the use of the improvements, the invention consists in the parts and' combinations thereof hereinafter set forth and claimed, with the r understanding that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as definedin the appended claims.

In order to make theinventi'on more clearly understood, there are shown in the accompanying drawing, means for carrying the invention into practical use, without limiting the improvements in their useful application to the particular construction, which, for the purpose of explanation, have been made the subject of illustration.

In the accompanying drawing:

Fig. lis a longitudinal sectional v iew vthrough a propeller hub'embodying the invention;

Fig. 2 is a transverse sectional view taken on line 2--2 of Fig. l; and

Y Fig. 3 is an enlarged fragmentary'view partly in elevation and parrtly in section of the means for anchoring the propeller blades in the hub.

Referring to the drawing, the improved propeller hub is shown as comprising a forward portion It which is xed to a tubular main drive shaft I I by keys I2, a-unitary intermediate portion I3 which is secured to the forward portion I by longitudinally extending bolts Il and a holand-intermediate portions I and I3 of the hub.

The intermediate portion I3 of the hub is pro- ;vlded with a plurality of radially extending bores formed with a reduced end 25 on Which-a bevel gear 26 is splined and an inner threaded stud 21 onto which a nut 28 is screwed for abutting engagement with the bevel gear 26 to prevent the displacement of the latter. A malleable lock washer 28 (Fig. 3) is interposed between the bevel gear v26 and the nut 28 and is provided with a series of inner and outer circumferential tongues 3l and 3l adapted to enter spline recesses formed in the reduced portion 25 of the root and in corresponding recesses in the periphery of the nut so as to prevent the unscrewing of the nut.

In assembling this portion of the apparatus,

the outer bearing 2| is iirst slipped onto .the root portion 24 and the root inserted'in the bore I9. The inner bearing 20 is then 'inserted through the openl rear end of the hub before it is closed by the hub cap I5 and slipped over the root and placed in its seat. The bevel gear 26 is next mounted on the reduced portion 25 of the root and the lock'washer 29 with alternate tongues 3l bent outwardly at right angles to the plane of the washer is positioned with the tongues 30 inserted in their recesses in the reduced end 25. The nut is then screwed up until 4the bevel gear 2B, being forced against the inner bearing 20,

draws the parts together the. desired amount. The unbent tongues 3| are then bent inwardly into the recesses in* the nut. A packing washer 32 of any preferred type is interposed between the blade 23 and the h'ub to, prevent the escape of lubricant'or the infiltration of water.

The blades 23 may be rotated any desired amount in the hub in order to vary their pitch by means of a quill or control shaft 33 which exiow after or hub cap portion I5 of streamline eon-l guration which is secured to the intermediate portion i3 by screws I5. This hub structure is maintained against axial displacement by means of a split collar I1 engageable with a circumferential groove or channel I8 formed in the main drive shaft and clamped between the forward tends coaxially through the drive shaft II and is rotatable therein. This shaft is provided with a squared extremity 34 on which a bevel pinion 35 is slidably but nonrotatably mounted for inter- I'neshing engagement with each of the bevel gears 2B. A cylindrical bushing 36 is mounted on the extreme rear end of the squared' end 34 of the shaft 33 and is mounted in a support 31 carried by a spider 3l formed integrally with the hub cap portion I5.' The squared end of the shaft 33 rotaies in the bushing as, the latter, togetnerwim the support 31, me

ely functioning asia steady-.

ing means for the rear end of the shaft 33. 'I'he bushing 36 is also formed with a flange 33 at its forward end for abutting engagement with the bevel pinion 35, the construction being such that the face of the ange 38 may be dressed down or the space between the iiange and the pinion shimmed up by adaptersV so that when the hub cap I5 is secured in positionv the pinion 35 will be held in accurate intermeshing engagement with bevel gears 26 without lost motion or play.

Although the bevel pinion 35 meshes with each of the bevel gears 26 so as to cause the propeller blades 23 to turn in unison when the pitch thereof is altered, additional means is provided to prevent binding of the parts which may be caused by inltrations of foreign matter such as sand and the like. 'I'his consists of an idler bevel pinion l0 which is rotatably mounted on a reduced portion Il of the main drive shaft ll for intermeshing engagement with each of the bevel gears 26 at points diametrically disposed from the bevel pinion, 35.

The hollow hub cap I5 is iiiled with a supply of lubricant which passes through the spider 38 to the moving parts of the propeller. Inward or outward leakage between the hub cap and the portion I3 of the hub is prevented by a packing ring 42 which is secured to the yhub cap by screws 43.

It will be understood that the above description and accompanying drawing comprehend only the general and preferred embodiment of the invention and that various changes in construction, proportion and arrangement of the parts may be made within the scope of the appended claims without sacrificing any of the advantages of the invention.

The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

1. A variable pitch propeller comprising a main drive shaft; a hub carried by said shaft, said hub embodying a forward portion keyed to said drive shaft, a unitary intermediate portion xed to said forward portion and an after streamlined cap portion fixed to said intermediate portion; and said drive shaft having a circumferential groove therein; a multipart thrust collar engageable with said groovev and clamped between the forward and intermediate portions of said hub for preventing `axial movement of said hub; a plurality of blades having root portions mounted in the intermediate portion of said hub for free rotation about radially extending axes completely throughout 360 in opposite directions tovary the pitch thereof; a bevel gear fixed to the inner end of each of said root portions; aquill shaft extending through vand rotatable in said drive shaft and having its after end rotatably and slidably journalled in the after cap portion of said hub; a bevel pinion slidably keyed to the after end of said quill shaft and meshing with each of said bevel gears; and a second bevel pinion rotatably mounted on said drive shaft for engagement with said bevel gears and diametrically opposed to said first mentioned bevel gear to uniformly transmit powerfrom oneof said bevel gears to another.

2. A variable pitch propeller comprising a main drive shaft; a hub carried by said'shaft.

.said hub embodying a forward portion keyed to said drive shaft, a unitary hollow intermediate portion fixed to said forward portion and an after hollow streamlined cap portion iixed to said intermediate 'portion and -communicating with said intermediate portion for containing a supply of lubricant for the moving parts of said propeller; and said drive shaft having a circumferential groove therein; a multipart thrust collar engageable with said groove and clamped between the forward and intermediate portions of said hub for preventing axial movement of said hub; a-plurality of blades having root portions mounted in the intermediate portion of said hub for free rotation about radially extending axes completely throughout 360 in opposite directions to vary the pitch thereof; a bevel gear fixed to the inner end of each of said root portions; a spider carried by said cap portion; a support carried by said spider; a quill shaft extending through and rotatable in said drive shaft and having its after end rotatably and slidably journalled in said support; a bevel pinion slidably keyed to the after end of said quill shaft forward of said support and. meshing with each of said bevel gears;

and a second bevel pinion rotatably mounted on said drive shaft for engagement with saidv bevel gears and diametrically opposed to said first mentioned bevel -gear to uniformly transmit power from one of said bevel gears to another.

ROBERT J. RUTHS. HARRY L. DODSON. 

